This code shows the alert whenever the dateacquired is blank AND the publishdate is either "in the present month" or "in the future". We do this by replacing the number for the present day of the month with "00" then see if the publishdate is greater.

"The substring function returns the substring of the first argument starting at the position specified in the second argument with length specified in the third argument."
substring(/data/@unformatteddate,1,6) = substring("20170331",1,6) = "201703"